<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <style>
        body {
            background-color: #000;
            margin: 0;
            overflow: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
            height: 100vh;
        }
        
        .ping-pong-ball {
            width: 50px;
            height: 50px;
            background-color: #f00;
            border-radius: 50%;
            position: absolute;
            animation: pingpong 2s ease-in-out infinite;
        }

        @keyframes pingpong {
            0%, 100% {
                left: 0;
                background-color: #f00;
            }
            50% {
                left: calc(100% - 50px);
                background-color: #00f;
            }
        }
    </style>
</head>
<body>
    <div class="ping-pong-ball"></div>
</body>
</html>
